The present invention relates to oral hygiene compositions. More particularly, the present invention relates to oral hygiene compositions which prevent and control mouth odor, calculus, plaque and caries and contain active zinc ions and fluoride ions. These compositions are also effective at preventing gingivitis and periodontal disease.
The use of soluble fluoride salts, such as stannous fluoride, sodium monofluorophosphate and sodium fluoride, to reduce the incidence of dental caries in the general population is a well-known and ongoing endeavor. The administration of these fluoride compounds takes many forms, including the fluoridation of drinking water, professional treatment by dentists and incorporation in oral hygiene compositions such as dentifrices and mouthrinses.
It is also known that zinc plays a role in dental care. For example, in U.S. Pat. No. 4,160,821 issued July 10, 1979, there is disclosed a composition for treating gingivitis comprising a vehicle containing a high concentration of glycerol and a zinc salt, such as zinc chloride, that is soluble in the glycerol.
In an article entitled "Inhibition of Plaque Growth by Zinc Salts," Journal of Periodontal Research, Vol. 18, pp. 634-642, 1983, Harrap et al. reported that solutions of zinc salts reduced plaque by 30% along the gingival margin. In "Effect of Some Polyvalent Cations of Plaque Formation In Vivo", Scandinavian Journal of Dental Research Vol. 186, pp. 103-107, 1978, it is indicated that mouthrinses containing either ZnCl.sub.2 AlCl.sub.3, MgCl.sub.2, SnF.sub.2 or SnCl.sub.2 exhibited significant plaque reducing activity. An oral rinse containing 1.0% zinc salts (as the phenolsulphonate) or 0.125% zinc complex with tribromsalan was found clinically to reduce mean calculus scores by about 60% and 53% respectively, in two consecutive three-month trials as reported by Picozzi et al. in an article entitled, "Calculus Inhibition in Humans", Journal of Periodontology, Volume 43, pp. 692-695, 1972. Zinc compounds (as 1% zinc phenolsulfonate and 0.125% zinc tribromsalan) formulated in an aqueous mouthwash significantly delayed the development of gingivitis in a test group compared to a placebo by Fischman et al., Journal Periodontology, Vol. 44, pp. 535-539, 1975.
In British Patent Specification No. 1,373,003, published Nov. 6, 1974, there is disclosed a dentifrice composition having activity against plaque and calculus on a tooth surface comprising a sparingly soluble zinc salt which is defined as a zinc salt of an acid, other than zinc fluoride or its hydrates, having a water solubility greater than that of zinc phosphate and less than 1 gram of zinc per 100 ml of water at 20.degree. C. and a mixture of detergents. The dentifrice may also contain a compatible abrasive such as alumina and other conventional toothpaste ingredients. U.S. Pat. No. 4,146,606, issued Mar. 27, 1979, relates to a pharmaceutical composition for dental use that can, inter alia, suppress dental caries, this composition comprising a strontium compound, a zinc compound, tannin and, optionally, a fluorine compound.
U.S. Pat. No. 4,138,477, issued Feb. 6, 1979, discloses a composition to prevent and control mouth odor, which is also said to be effective in preventing calculus, plaque, caries and periodontal disease, containing as the essential agent a zinc-polymer complex formed by the reaction or chelation of a zinc compound with an anionic polymer containing carboxylic, sulfonic and/or phosphoric acid radicals. The composition may also include, inter alia, a fluorine-containing compound that protects the teeth against decay. U.S. Pat. No. 4,396,599 issued Aug. 2, 1983, describes anticaries compositions including dentifrices containing a fluoride compound and a zinc compound with a ratio of zinc ion to fluoride ion of at least about 7:1 by weight.